There is known an OTT (Over The Top) as a data delivery scheme capable of delivering a content such as image data and audio data irrespectively of a service form of each telecommunications carrier. A content delivered by the OTT is referred to as “OTT content,” and an image (video) data delivery service using the OTT is referred to as OTT video or “OTT-V (Over The Top Video).”
A DASH (Dynamic Adaptive Streaming over HTTP) standard is present as a data streaming delivery standard compliant with the OTT-V. The DASH is the standard related to adaptive streaming delivery using a streaming protocol based on an HTTP (Hypertext Transfer Protocol).
For adaptive streaming, a content delivery server such as a broadcast station creates segmented files of a video content at a plurality of bitrates and a manifest file that describes attribute information and URLs (Uniform Resource Locators) of these files, and provides the files to a client in order to allow playback of contents in various clients which become a destination of data delivery.
The client acquires the manifest file from the server, selects a content at an optimum bitrate according to a size of a display unit of the client or an available communication band therefor, and receives and plays back the selected contents. Bitrates can be dynamically changed in response to a variation in a network band, so that the client can receive an optimum content depending on a situation by switching as needed and realize playback of the video content with reduced frequency of the occurrence of video interruption. It is noted that the adaptive streaming is described in, for example, PTL 1 (JP 2011-87103A).
The development and standardization of a system for enabling transmitting and receiving a content of a broadcast program and the like from a transmitting device such as a broadcast station or another content server to a receiving device such as a television, a PC (Personal Computer) or a mobile terminal by using uni-directional communication via a broadcast wave or the like, or using bi-directional communication or uni-directional communication via a network such as the Internet are currently actively underway.
Examples of a conventional technique disclosing a technique for realizing data delivery via a broadcast wave and a network include PTL 2 (JP 2014-057227A).
As a standard related to data delivery systems via the broadcast wave and the network, the standardization of ATSC (Advanced Television System Committee) 3.0 is currently underway.
In relation to the ATSC 3.0, a configuration that can receive signaling data including control information and the like for ATSC broadcasting and enables various controls by the signaling data by implementing middleware that executes processes such as a process for receiving ATSC 3.0 broadcasting in a receiving device that implements ATSC 3.0-compatible physical layers (ATSC-PHY) is under consideration.
Specifically, the configuration that can realize a process for outputting a broadcast content using an application program used in the Internet or the like or so-called client application as it is, and a data process using various applications provided via the broadcast wave and the like under the control of the signaling data is under consideration.
For example, the ATSC 3.0-compatible physical layers (ATSC-PHY) and the ATSC 3.0 broadcast receiving middleware are implemented in a server (such as a PC, a TV (Television), a tablet, or a smartphone as well as a dedicated server) installed in an ordinary house or a hot spot and receiving broadcast services.
Once such a server receives an ATSC 3.0 broadcast service, the server transfers broadcast received data to a user device (such as a PC, a TV, a tablet, or a smartphone) via a network (such as LAN (Local Area Network)/WiFi (Wireless Fidelity) such as a home network or a hot spot).
The user device that has received the broadcast received data transferred via the server can play back the broadcast content using an application (such as an ATSC 3.0 DASH client application) running on a playback control unit or an application control unit of the user device and execute various applications delivered by broadcasting.
A broadcast server such as the broadcast station that transmits a broadcast program can provide not only program data (broadcasting content) but also an application (referred to as “playback application, player application, or the like”) that executes a program data playback process to the receiving device (client) such as the TV that is the user device.
For example, a broadcast station A provides a playback application a that is applicable only to the playback of a content provided by the broadcast station A to the receiving device (client) via the broadcast wave or the like.
The receiving device (client) can receive the playback application a, and play back the content provided by the broadcast station A by a playback process to which the received playback application a is applied.
A broadcast station B provides a playback application b different from the playback application a, and the receiving device (client) play backs a content provided by the broadcast station B using the playback application b when playing back the content.
Furthermore, the broadcast server can provide not a playback application per broadcast station but also a playback application per specific program. The receiving device (client) play backs a specific program while applying a program-enabled playback application received from the transmitting device to a playback process when playing back the program.
However, the receiving device (client) such as the television originally holds a playback application or a so-called residential (resident type) playback application that is embedded in the receiving device at a time of manufacturing, and has conventionally and normally executed a process for playing back a program using one residential playback application irrespectively of channel setting.
If the broadcast server provides the playback application per broadcast station or per program in the future as described above, it is essential for the receiving device (client) to select one playback application applied to the playback of each program from among a plurality of playback applications and to use the selected playback application.
If the receiving device fails to acquire or select a correct broadcast station-enabled or program-enabled playback application, the failure causes a situation in which the receiving device is unable to play back a correct program.
For example, if a playback application that should be applied to the playback of a program provided by a certain broadcast station is limited to an application delivered and provided by the broadcast station and the receiving device incorrectly uses the residential playback application, this failure causes a situation in which the receiving device is unable to play back a correct program.
However, under a present situation, specifications for configurations of processes such as a process for providing a playback application and a process for acquiring, selecting, and using the playback application by the receiving device are not specifically defined yet.